You may love it or loath it, but the contrasts of Istanbul are impossible to ignore. It is a city where history meets modernity, where palaces, mosques and cathedrals lie next to chaotic bazaars, steaming hamam baths and small shops selling things you never need. It is a city that, despite plague, war and economic regression for more than 2000 years has always stood up against the test of time. Today, it is one of the 25 largest cities in the world and the bridge (literally) between Europe and Asia.2000 years and still relevantIn a new book on urbanism and environmental dynamics, centre researchers Stephan Barthel andSverker Sörlin have looked at how Constantinople has succeeded to persist and develop despite regularly occurring disturbances.Their findings demonstrate that in the quest for more ecologically sound urbanisation, urban planners of today have a lot to learn from this ancient city.“Our message from having revisited the resilience history of Constantinople during more than three millennia is that the keeping of green space for tacit co-production and community-based relationships to land and water have been essential properties for long-term survival and success", Barthel and Sörlin say.Strategic location and smart food productionConstantinople is a city whose origin can be traced back to the establishment of Greek cities and colonies in early antiquity. Eventually it became the capital of the East Roman Empire and since then its role in the region has never really diminished.One answer to this long-term resilience is the city's capacity to produce significant amounts of food within the urban settlement itself rather than having to rely on others.The productivity of gardening, livestock keeping and fishing proved essential to how well the city could cope in times of stress. Even in periods with population peaks such as the early 6th and 12th centuries, Constantinople was resilientin terms of food and water when trade was cut off“The rulers of the city invested not only in military infrastructure but also in systems for supplying and storing food and water. And when sieges were efficient and supplies ran dry, there were still possibilities to cultivate food within the city walls and catch fish in the Golden Horn. Hence Constantinople had a variety of options to sustain the city with food." Social memory is kingKnowledge and values on how to cope with crises were also kept in multiple groups of the society. This memory of past crises consequently led to new and innovative ways of providing food to the inhabitants.

The missing thing in resilience theoryBarthel and Sörlin's study not only offers city planners and urban developers an inspirational perspective on how to turn urban areas greener, it also puts urban resilience theory itself under a critical microscope.

“What is largely still missing in social-ecological resilience theory is a treatment of cities and urban areas. This includes the historical lessons that can be drawn from distant urban pasts in regard to sustaining ecosystem services during times of hardship and crisis", Barthel argues.

Another futile approach identified in their work is to strive for urban resilience in isolation without taking into account the environmental burdens of cities on the biosphere. There is a lot to learn from ancient history in this regard, not the least to create a fresh critique to research that assumes cities to be floating in an ecological vacuum.“The urban environmental histories of cities like Constantinople are not templates for future planning, but as resources of ideas, wisdom and indeed also grave mistakes. Schools of innovation, architecture, construction and urban planning must be further 'ecologised' if sustainable development is to have any iota of meaning", Barthel and his colleagues conclude.

See video interview with Ann Kinzing, associate professor of Arizona State University, on the challenges and opportunities in turning urban systems more sustainable: